Chip modules comprising a chip arranged on a substrate are basically used in all cases in which simplified electric contacting of the chip is to be facilitated by means of substrate connecting leads which are substantially larger than the chip terminal surfaces. Thus such chip modules are used, for example, in chip cards and via the exposed substrate connecting leads extending over the card surface permit "external contacting" of the chip accommodated inside the chip card by the arrangement on the rear side of the substrate. Such chip modules are also used to construct so-called contactless chip cards in the case of which the substrate connecting leads provide for simplified contacting with an antenna coil arranged inside the card body. Naturally such chip modules can also be used, for example, to construct a so-called "combi-card" in the case of which external contacting for contact access to the card chip as well as internal contacting for contactless access to the chip via the antenna coil are facilitated by means of the substrate.
The combination of a chip with the substrate to form the chip module results in a composite structure, the thickness of which is relatively great compared to the thickness of the chip and the thickness of the substrate and which must be accommodated in a card body with defined outer dimensions. To ensure that the accommodation of a chip module in a card body imposes the least possible restrictions upon the possibilities of further component installations in the card body, it thus proves essential for the chip module to be designed to be as thin as possible.
A disadvantage of the known, relatively thick chip modules is that simply by virtue of their relative thickness, they have greater bending resistance compared to the flexible card body and therefore when the card body is subjected to bending stress as frequently occurs in everyday use, in particular when the substrate is arranged in the card surface as in the case of a contact card, the connection between chip module and card body can be stressed to a high level, leading to the detachment of the chip module from the card body. U.S. Pat. No. 5,155,068 has disclosed a chip module and process for the production of a chip module wherein the connection between chip and substrate is established in two consecutive process steps in which firstly the electric contacting of the bonding pads of the chip to terminal surfaces ofthe substrate is performed and then the mechanical connection between the chip and the chip substrate is effected by embedding the entire chip into a synthetic resin compound surrounding the chip. As a result of the embedding of the chip into the synthetic resin compound surrounding the chip, during the following abrasive processing ofthe rear side ofthe chip it is necessary to abrasively remove the material surrounding the chip in addition to the chip material.
JP-A-63 147 352, referred to in "Patent Abstracts of Japan", also discloses a process for the production of a chip module wherein the connection between chip and chip substrate is established in two process steps and wherein the chip is embedded in a synthetic resin compound for mechanical connection to the chip substrate.
EP-A-0 207 853 has disclosed a process wherein a plurality of chip modules are produced continuously using a film carrier.